I don't understand there are so many bounty in bounty section. Because a YouTuber made video and I saw. He says make account and than earn money with bounty and I don't have knowledge?
How old was the video that you saw? As I have read from this thread and somewhere in the forum, there was a time when the bounty section was very interesting, rewarding participants with huge amounts of money, and sometimes up to 1-5% of the total token allocation was given to airdrops and bounties, but right now there isn't much of a reward coming out of bounties considering the number of participants that are also partaking in them. The reward will be very small and won't be worth much, so I don't think anyone will be making any new videos regarding how to earn from bounty now.
Another thing is that it seems that back then, there were many good and potential projects that tried so hard to fulfil their promises rather than just having it in mind to scam others and rug-pulling when they hit their target.
Currently, there is little coming out of bounty programmes, but they are still not completely useless, and they are not worth all of your time. If you want to give it a try, you can DYOR on a few of the projects, select the ones you will like to participate in, and see what you can get from them at the end of the campaign. But don't expect more from them. If the few that you pick among many happen to give you little things, then you can decide if you are to continue or if you are to let go of them.